DE69805992T2 - POWER AMPLIFICATION SYSTEM WITH INTELLIGENT CONTROL OF AMPLIFIER MODULES - Google Patents

Description

FIELD OF INVENTION

The present invention relates generally to the field of wireless telecommunications and, more particularly, to the field of power maintenance in the amplification of communication signals.

BACKGROUND OF THE INVENTION

Systems with multiple linear power amplifiers have numerous applications. For example, four-module multi-channel linear amplifier systems are used in cellular telephone base stations or "cell sites." Such base stations or cell sites are well known and are described, for example, in George Calhoun, Wireless Access and the Local Telephone Network 128-135 (1992), which is hereby incorporated. Such amplifier systems are used in cell sites to amplify multiple radio frequency (RF) signals of various and different frequencies or channels or carriers. Such a system typically includes a splitter, a plurality of linear amplifier modules, a combiner, a controller for the splitter/combiner, and a monitor and control module. Examples of such a system include the Spectrian MC160A series of multi-carrier power amplifiers and the PowerWave MCA9000-400 series of linear amplifier systems.

In such a system, an "input signal" is fed into a divider. This input signal comprises one or more radio frequency signals of different frequencies. In other words, this input signal can be a multi-channel signal. These radio frequency signals can be in any desired format or protocol, including the Advanced Mobile Phone Service (AMPS), Time Division Multiple Access (TDMA) standards. The divider divides the input signal into two or more resulting signals. The resulting signals have the same frequency as the input signal, but the power or amplitude of the input signal is divided equally among the resulting signals.

The divider in a typical four-module linear amplifier system, such as the MCA9000-400 Series PowerWave Four-Module Linear Amplifier System, has four outputs, each of which is coupled to one of the four linear amplifier modules. The divider is configured according to the number of linear amplifier modules that are coupled to the divider and operational. A divider/combiner controller, implemented, for example, by a microprocessor or at the circuit level, monitors the number of amplifier modules that are coupled to the divider and operational and configures the divider and combiner accordingly. In a four-module system where all four modules are operational, the divider/combiner controller configures the divider for four modules so that the divider divides an input signal into four resultant signals, each of which has the same frequency content as the input signal and one-quarter the power. If the divider is configured to correspond to three coupled and operational amplifier modules, the divider divides the input signal into three resultant signals, each of equal power corresponding to one-third of the input signal. Similarly, if the divider is configured for two modules, the divider divides the input signal into two signals, and if the divider is configured for one module, it does not divide the signal.

Each of the four modules amplifies the signal input to that module to a desired level. The amplified signals are coupled to a combiner. The divider/combiner controller configures the combiner according to the number of power modules coupled to the divider and operational. Thus, in a four-module system, the divider/combiner controller logic configures the combiner to operate in such a system. Accordingly, the combiner combines the four amplified signals into a single output signal for transmission. Typically, this combined output is delivered to a transmitting antenna via an antenna interface circuit.

In addition, a monitoring and control device is used in such a system to supply and control the operating power to each of the modules, to monitor each of the modules, to enable or disable all of the modules, and to inform the operator when the system is operating outside of parameters. This device can also be used together with the divider/combiner control device or instead of it to configure and reconfigure the divider and combiner.

In the systems used in traditional cell phone stations, the monitoring and control equipment does not activate or deactivate individual power amplifier modules independently. All modules are either active or all modules are inactive.

The multi-channel, multi-amplifier linear amplifier systems used in traditional cell sites require significant power and are consequently expensive to operate. A traditional cell site power supply typically delivers power to the system at 24-27 VDC and the current required by the system at any given time. The power required by the system typically varies daily over time according to subscriber usage of the system. During peak hours, when subscriber demand is highest, the system may require 1500-2500 watts. During off-peak hours, the system power requirement may be approximately 150 watts, drastically less than peak hour demand.

A large portion of the power required to operate a four-module linear amplifier system can in some respects be considered a common requirement, as it simply keeps all four of the power amplifier modules in an active state when the system is operating. During peak hours, all four power amplifiers are often required to amplify the signals carried by the system. Therefore, it is often necessary to keep all four power amplifiers in the active state during peak hours. During off-peak hours, However, the system may only require one or two of the power amplifier modules to operate adequately. Thus, only one or perhaps two of the amplifier modules may need to be active during off-peak hours. Thus, if only the required amplifier modules were kept active, significantly less power would be required for the common use.

As mentioned above, conventional systems are not designed to control the activation or deactivation of individual power amplifier modules. Rather, all modules remain in the same operating state at any given time. For example, in a conventional four-module system, all four modules remain in the active state both during and off-peak hours. Since all modules are either active or inactive at any given time, the power amplifier modules consume more power than is required to adequately operate the system. Conventional systems therefore use power inefficiently and are therefore more expensive to operate than necessary.

US-A-5 304 943 is recognized as the closest prior art to the present invention and discloses a linear power amplifier system comprising a divider, a plurality of amplifiers and a combiner, the input of each amplifier being controlled by a switch controlled by a control device.

SUMMARY OF THE INVENTION

A linear power amplifier system having an input; a splitter having an input and a plurality of outputs; a plurality of linear power amplifier modules, each power amplifier module including an input and an output, each amplifier input coupled to at least one splitter output; a combiner having a plurality of inputs and an output, each combiner input coupled to at least one amplifier output; a controller having at least one input and at least one output, the system input coupled to the splitter input, each controller output coupled to at least one amplifier module, and the control device is constructed such that, upon detection of a predetermined signal at at least one control device input, it provides a predetermined control signal at at least one control device output to at least one amplifier module, the operating state of each amplifier module responsive to its predetermined control signal from the control device.

Linear power amplifier systems according to the present invention utilize power more efficiently than conventional systems. Such efficiency allows for lower operating costs of the linear power amplifier systems according to the present invention than those of conventional systems.

The system and method according to US-A-5 304 943 does not disclose the coupling of each output of the control device to at least one amplifier module.

Structural differences between systems according to the present invention and conventional systems include the communication lines that facilitate independent control of individual power amplifier modules. Structural differences also include the structure that implements a splitter, a combiner, and individually controlled power amplifier modules in a mobile communication cell site.

Systems according to the present invention use intelligent control of linear amplifier modules to increase power consumption efficiency. This intelligent control occurs after evaluating conditions at one or more points inside and, if desired, outside the system. These conditions can be a wide variety of signal types including CDMA, TDMA and AMPS. Systems according to the present invention are capable of evaluating these or more signal types and intelligently controlling individual amplifier modules according to this evaluation. These systems use structures that split and combine RF signals.

Systems according to the present invention use power more efficiently than conventional systems by, among other things, enabling/disabling individual power more in a manner that corresponds to the actual capacity required; by intelligently controlling several power amplifier modules of the system so that individual modules can be set to the active or inactive state as desired, regardless of the state of other modules; and by requiring less power to operate than conventional mobile communications power amplifiers.

According to a first embodiment of the present invention, a second control device is coupled to the divider and each amplifier module and is arranged such that, upon detecting the operating state of each amplifier module, the second control device configures the divider according to the operating state of each amplifier module. The second control device can also be coupled to the combiner and is arranged such that, upon detecting the operating state of each amplifier module, it configures the combiner according to the operating state of each amplifier module.

According to a second embodiment of the present invention, the system includes a common control module with at least one common control output and at least one common control input, wherein at least one common control output is coupled to at least one input of the control device. The common control module can also be coupled to each amplifier module and to the divider and configured such that, upon detecting the operating state of each amplifier module, the common control module configures the divider according to the operating state of each amplifier module. The common control module can further be coupled to each amplifier module and to the combiner and configured such that, upon detecting the operating state of each amplifier module, the common control module configures the combiner according to the operating state of each amplifier module.

Furthermore, according to the present invention, a subscriber station comprises: an input; a linear power amplifier system having an input and a plurality of outputs; a plurality of linear power amplifier modules, each amplifier module including an input and an output, and each amplifier including a input is coupled to at least one divider output; a combiner with a plurality of inputs (300, 301, 302, 304) and one output (56), each combiner input being coupled to at least one amplifier output; a control device which contains at least one input and at least one output, the station input being coupled to the divider input; a modulation system; a radio system and an antenna, in which the modulation system is coupled to the station input; the combiner is coupled to the radio system; the radio system is coupled to the antenna; the or each output of the control device is coupled to at least one amplifier module; and the control device is set up such that, upon detection of a predetermined control signal at at least one input of the control device, it provides a predetermined control signal at at least one output of the control device to at least one amplifier module, the operating state of each amplifier module responding to its predetermined control signal from the control device.

Furthermore, according to the present invention, a control device for a linear power amplifier system comprises: an input; a divider with an input and a plurality of outputs; a plurality of linear power amplifier modules, each amplifier module comprising an input, an output and a control terminal, and each amplifier input being coupled to at least one divider output; a combiner with a plurality of inputs and an output, each combiner input being coupled to at least one amplifier output, the system input being coupled to the divider input; the control device comprises at least one input and at least one output; each output of the control device is coupled to the control terminal of at least one amplifier module during operation; and the control device is configured such that, during operation, upon detection of a predetermined signal at at least one input of the control device, it provides a predetermined control signal to at least one output of the control device of at least one amplifier module in order to control its operating state.

Other objects, features and advantages of the present invention will be disclosed by the appended claims and by way of example in the description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 schematically shows an embodiment of linear power amplifier systems of the present invention with four power amplifier modules, a controller monitoring the system output, a single communication line between the controller and the modules, and a controller of the divider/combiner monitoring the modules and configuring the divider and the combiner.

Fig. 2 schematically shows a second embodiment of systems of the present invention with four power amplifier modules, a controller monitoring the system output and the modules and configuring the divider and combiner, and several communication lines between the microprocessor and the modules.

Fig. 3 schematically shows a third embodiment of systems of the present invention with four power amplifier modules, a control device monitoring both the system output and the system input and configuring the divider and combiner accordingly, and a single communication line between the microprocessor and the modules.

Fig. 4 schematically shows a fourth embodiment of systems of the present invention with four power amplifier modules, a controller monitoring the output of a common control module and a single communication line between the microprocessor and the modules, where the common control module monitors the transmission site communication bus and configures the divider and combiner.

Fig. 5 shows schematically a fifth embodiment of systems of the present invention with four power amplifier modules, a microprocessor monitoring the output of a common control module and a single communication line between the microprocessor and the modules, in which the common control module monitors the communications directed from the central operating point to the common control module via a receiving point and configures the divider and combiner.

Fig. 6 shows schematically a subscriber station with a linear amplifier system according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides intelligent control of multiple linear power amplifier modules. The controller, which may be implemented in a microprocessor, in a logic circuit, or in distributed processing using artificially intelligent or rule-based implementation, neural networks, or any other desired mode or control process, monitors the system and other factors if desired and, based on their monitoring and evaluation, provides control of the system's amplification capacity. By activating only the amplification capacity required for adequate operation of the system, this intelligent controller provides a linear power amplifier system that uses power in a more efficient manner than conventional systems.

According to the preferred embodiment, a four-module, multi-channel linear amplifier system is of the type used in cell sites for cellular telephones. However, the present invention may be implemented in a variety of other systems, including PCS sites, other mobile radio stations, systems with more or less than four modules, and systems used in locations other than mobile radio stations.

In a preferred embodiment, the control device is coupled to one or more circuits or components ("points") inside and, if desired, outside the system to monitor the various states inside (and, if desired, outside) the system, such as inputs or outputs at various points of the system. The control device evaluates the state at such point(s) to determine how many of the power amplification modules are required to meet the demand on the system at that time. The point(s) to which the control device may be coupled include points in the system input, the system output, the output of a common control module, points external to the system, or a combination thereof. Conditions that may be monitored in the system preferably include signal power at those points. After determining how many modules are required for adequate operation of the system, the control device activates the respective modules needed at that time and deactivates the modules not needed at that time. As in conventional systems, a control device, such as one implemented in a microprocessor or other logic circuit, monitors the modules. The control device configures the divider and combiner according to the number of modules that are present and operational.

The control algorithm for the divider and combiner, which is carried out by the control device or the control device for the divider/combiner according to the present invention, must be such that the dynamic reconfiguration of the divider and combiner and the dynamic activation and deactivation of the amplifier modules are controlled so that the gain factor in the system is maintained. In particular, if the divider and the dynamic activation and deactivation of the amplifier modules are not carefully controlled, the modules may be overloaded and damaged.

Some conventional dividers and combiners have control inputs that can be used according to the present invention to reconfigure the divider and combiner according to the number of amplifier modules in the active state. Other dividers and combiners require a new control interface that can be coupled to a controller or a controller for the divider/combiner according to the present invention.

The design, construction and operation of systems according to the present invention are flexible depending on the needs of the application to which the invention is directed. xible. The number and location of the points within the system to which the control device is coupled may vary. The control device responds to specific conditions or ranges of conditions at the points to which the control device is coupled. Personnel intervention, external control intervention, or other external inputs may be used to correct or modify the manner in which the modules are activated regardless of conditions in the system reflecting particular capacity requirements. The control device, whether distributed or not, may also be implemented to evaluate and adjust the operating state of the modules at selected time intervals, random time intervals, or preferably continuously.

Fig. 1 shows a four-module linear amplifier system 10 which best embodies the present invention. The system 10 includes a divider 16, four power amplifier modules 28, 29, 30, 31, a combiner 54, and a controller 62. When the system is in operation, one or more radio frequency signals (not shown) in a format such as AMPS, TDMA, or CDMA are provided on an input line 14 to the divider input 18 in the divider 16. The divider 16 allocates the signals to a plurality of divider outputs 20, 21, 22, 23 according to the volume of the input signals, the power attenuation of the signals, which amplifier modules are in the active state, and other factors.

The divider in the system shown in Fig. 1 has four outputs 20, 21, 22, 23. These outputs 20, 21, 22, 23 are coupled to four linear amplifier modules 28, 29, 30, 31.

Each linear amplifier module has at least two operating states, the active or amplifying or "on" state and the inactive or open or "off" state. An amplifier module in the active state amplifies the input signal at a preselected gain factor. Preferably, an amplifier module that is in the inactive state essentially acts as an open loop and transmits no signals.

Each module has a control terminal. The operating state of a module depends on the signal received through the control terminal 68, 69, 70, 71 of that module. If a signal preselected to cause a module to go into the active state is applied to the control terminal of the module, the module will go into the active state if it is in the inactive state and will remain in the active state if it is already in the active state. If a signal preselected to cause a module to go into the inactive state is applied to the control terminal of the module, the module will go into the inactive state if it is in the active state and will remain in the inactive state if it is already in the inactive state. The system and modules can be designed and programmed to respond to a wide variety of signals in a desired manner.

Each module in the active state amplifies the signal input to that module and provides an amplified signal at its output. The outputs of the modules are shown in Fig. 1 as 42, 43, 44 and 45. The outputs 42, 43, 44, 45 are coupled to combiner inputs 300, 301, 302, 303. The amplified signals are fed from the outputs to a combiner 54. The combiner 54 combines the input signals and provides an output signal at combiner output 56. The combiner output 56 is the system output in the illustrated embodiment. The combiner output 56 can be coupled to an antenna circuit (not shown) that prepares the signal for antenna transmission.

The control device is preferably pre-programmed. The control device may monitor a condition such as the output signal of the combiner, including in particular the power level of the output signal, to determine how many active amplifier modules are required for sufficient operation of the system. In this case, the combiner output 56 is coupled to the input 64 of the control device 62. The control device evaluates the signal at its input 64 and transmits a control signal at its output 66 to the amplifier modules 28, 29, 30, 31. The control signal transmitted by the control device 62 depends on the signal that the control device 62 detects at its input. The control device 62 may be pre-programmed to evaluates the signal(s) at its input 64 to determine how many of the four power amplifier modules 28, 29, 30, 31 should be in the active state for adequate operation of the linear power amplifier system 10. For example, the controller may be programmed to determine that the system is likely to handle a certain number of calls when a given level of signal power is present at the system output, and that only two of the power modules are required to amplify signals for that number of calls.

If the control device 62 determines, based on the evaluation of the signal at its input 64, that only two of the four amplifier modules 28, 29, 30, 31 in the active state are required for sufficient operation of the linear power amplifier system 10, the control device 62 transmits a preselected signal to the control terminals 68, 69, 70, 71 of the amplifier module, which causes two modules 28, 29 to go into the active state and two modules 30, 31 to enter the inactive state. This signal can consist of analog or digital signals, which is selected during the design. Preferably, the signal is a digital signal. If the controller 62 determines that only one amplifier module in the active state is required, the controller transmits another preselected signal to the modules that causes one module to go into the active state and three modules to go into the inactive state. Similarly, if the controller determines that three amplifier modules in the active state are required, the controller transmits a corresponding predetermined signal to the modules, and if the controller determines that four modules in the active state are required, it transmits a corresponding predetermined signal to the modules.

The divider/combiner controller 400 is coupled to the amplifier modules 28, 29, 30, 31. Each amplifier module 28, 29, 30, 31 has an amplifier module state output 420, 421, 422, 423 that reflects the operating state of the corresponding module. The functionality 400 is also coupled to the divider 16 and the combiner 54. Coupling the functionality to the amplifier modules 28, 29, 30, 31 allows the functionality 400 to monitor the operating state of the modules and determine how many and which of the amplifier modules are in the active state. The functionality uses this information to to configure the divider 16 and the combiner 54 accordingly. Thus, if the controller 62 determines that only two amplifier modules are required for adequate operation of the system and activates two amplifier modules and deactivates two modules, the divider/combiner controller 400 detects that only two modules are in the active state and configures the divider and combiner accordingly. Thus, if only two amplifier modules 28, 29 are in the active state, the divider/combiner controller 400 configures the divider to split the input signal into two signals that are transmitted to only two divider outputs 20, 21. Likewise, the functionality 400 configures the combiner to combine signals at only two of its combiner inputs 300, 301. The system of Fig. 1 is an improvement over the conventional systems because it provides dynamic independent control of the individual amplifier modules as desired.

Fig. 2 shows another embodiment of the present invention. The system according to Fig. 2 operates in substantially the same way as the system of Fig. 1 described above. However, the control device of the system shown in Fig. 2 is constructed and operates differently than the control device described above. The control device shown in Fig. 2 has four control outputs 100, 101, 102, 103, each of which is coupled to one and only one amplifier control terminal 68, 69, 70, 71. In addition, the function of the control device 400 for the divider/combiner in Fig. 1 is performed by the control device 62 in Fig. 2.

If the control device 62 determines, upon evaluating the signal at its input 64, that only two of the four amplifier modules 28, 29, 30, 31 are required in the active state to adequately operate the linear power amplifier system 10, the control device 62 provides a digital 1 to two of its control outputs 100, 101 and a digital 0 to the other two 102, 103. Accordingly, a digital 1 is transmitted to the two amplifier control terminals 68, 69 and a digital 0 to the other two amplifier control terminals 70, 71. Each amplifier module is programmed to be in the active state when a digital 1 is present at its amplifier control terminal and in the inactive state when a digital 0 is present at its amplifier control terminal. If the control device 62 transmits two digital ones and two digital zeros, two of the modules 28, 29 are in the active state and two of the modules 30, 31 are in the inactive state.

If the control device 62 determines that only one amplifier module is needed in the active state, it transmits a digital 1 and three digital zeros, and thus one of the modules 28 is in the active state and the other three modules 29, 30, 31 are in the inactive state. Similarly, if the control device determines that three amplifier modules are needed in the active state, the control device transmits three digital ones and one digital 0, and thus three of the modules 28, 29, 30 are in the active state and the other module 31 is in the inactive state. If the control device determines that four amplifier modules are needed in the active state, the control device transmits four digital ones and no digital 0, and accordingly all four modules 28, 29, 30, 31 are in the active state.

In Fig. 2, the controller 62 is coupled to the splitter 16 and the combiner 54. In addition, the controller 62 is coupled to the four amplifier modules 28, 29, 30, 31. If the controller 62 determines that three amplifier modules are needed in the active state while making the determinations described in the previous paragraph, the controller configures the splitter 16 and the combiner 54 for operation with three amplifier modules in addition to communicating to the amplifier modules. In such a configuration, the divider divides the input signal into three signals at the divider outputs 20, 21, 22 and the combiner combines signals at three of the combiner inputs 300, 301, 302. If the controller 62 similarly determines that only one amplifier module is needed, the functionality 62 configures the divider 16 and the combiner 54 for operation with one amplifier module.

Fig. 3 shows another embodiment of the present invention. The system according to Fig. 3 operates in substantially the same manner as the system shown in Fig. 1. However, the controller 62 shown in Fig. 3 has two controller inputs 64, 65. One of the controller inputs 64 is coupled to the combiner output 56 in the same way as the single controller input 66. directional input is coupled to the combiner output in Fig. 1 and Fig. 2. The second controller input 65 of the system shown in Fig. 3 is coupled to the input line 14. Accordingly, the system input signal is transmitted not only to the divider input 18, but also to one of the controller inputs 65. Preferably, the controller 62 is pre-programmed with the gain of the system. The controller may also be pre-programmed to calculate the gain of the system from its input(s) and when appropriately connected, preferably as shown in Fig. 3. The controller 62 shown in Fig. 3 uses both the system output signal and the system input signal to determine how many amplifier modules should be in the active state and how many should be in the inactive state to provide the required gain for proper system operation. As discussed above, after such evaluation, the controller sends control signals to the modules to activate the required modules and deactivate the unnecessary modules.

Furthermore, the configuration of the divider 16 and the combiner 54 is controlled by the controller 62 according to Fig. 3. However, in the embodiment shown in Fig. 3, the functionality 62 is not coupled to the amplifier modules 28, 29, 30, 31. The modules 28, 29, 30, 31 are not monitored by the functionality 62 in determining how the divider 16 and the combiner 54 should be configured (however, the functionality 62 may monitor the modules for other reasons (not shown)). The controller configures the divider 16 and the combiner 54 after determining how many modules should be activated for sufficient operation of the system.

The figures herein show the preferred arrangement of the connections to the controller inputs. However, these connections may be made anywhere within the system. For example, the controller inputs could be connected to the four divider outputs and all outputs of the four amplifiers of the system shown in Figure 3. This would provide the controller with essentially the same information as if the controller inputs were connected to the system input line 14 and the combiner output 56 shown in Figure 3. The four connections to the divider output The four terminals on the divider output would provide substantially the same information as the terminal on input line 14, and the four terminals on the amplifier module outputs would provide substantially the same information as the terminal on combiner output 56.

Fig. 4 shows another embodiment of the present invention. The system according to Fig. 4 operates in substantially the same manner as the system shown in Fig. 1. However, the system shown in Fig. 4 includes a common control module 80. The common control module 80 serves to monitor and control individual parts of the system as desired. It can also be used to control the function of the control device by commands as desired. In Fig. 4, the common control module 80 includes two common control inputs 83, 85. One of the inputs 83 is coupled to the divider monitoring port 91. The divider monitor port 91 provides information in the form of one or more signals about the current and/or past operation of the divider 16. The coupling of the input 83 and the divider monitor port 91 allows the common control module 80 to monitor the operation of the divider 16. The second input 85 is coupled to the combiner monitor port 93 which provides information about the current and/or past operation of the combiner 54. The coupling between the combiner monitor port 93 and the second input 85 allows the common control module 80 to monitor the operation of the combiner 54. The common control module can also monitor individual lines such as the input line 14 (this is not shown).

The common control module 80 shown in Figure 4 includes two common control outputs 82, 84. One output 82 is coupled to a divider control port 90. The other output 84 is coupled to a combiner control port 91. The divider control port 90 allows an external device to control various aspects of the divider operation and the combiner control port 91 allows an external device to control various aspects of the combiner operation.

Modern cell sites can have several transmitters 200, 201, 202, 203 that communicate with a central operating site 210. Central operating sites or network Central operating stations 210 are used in cellular communications. The function and structure of central operating stations or network control devices and their use in wireless systems are described in George Calhoun, Wireless Access and the Local Telephone Network 129-135 (1992), which is incorporated herein by reference. The central operating station 210 monitors various cell sites and manages the operation of the cell sites. It may include a plurality of transmitters and receivers used in radio frequency communications, as well as computer hardware for monitoring and evaluating the operation of the cell sites and related information, and for appropriate communication with cell sites.

Fig. 4 shows four transmitters 200, 201, 202, 203. These transmitters are located at the cell site along with the system structure described above. The desired operating frequency and state for the transmitters 200, 201, 202, 203 are communicated to the transmitters from the central operating site 210. For example, the central operating site 210 may communicate that the transmitters operate at a certain frequency and that only two transmitters should be operating (or "on"). This is accomplished by the central operating site 210 communicating using radio frequency signals 212, with a receiver 202 located at the cell site. The receiver 202 in turn communicates with the transmitters via a communication bus 96. The receiver 202 transmits signals via the communication bus 96 to the transmitters 200, 201, 202, 203 to cause them to use the desired frequency and/or to enter the desired state.

The common control module 80 includes a common control input 81. The common control input 81 is coupled to the communication bus 96. Thus, the signals on the communication bus 96 are transmitted to the common control module 80 as well as to the transmitters 200, 201, 202, 203. Accordingly, the common control module 80 can monitor the communication between the receiver 202 and the transmitters 200, 201, 202, 203. This monitoring allows the common control module to determine the number of transmitters in operation and their transmission frequency. This information is evaluated by the common control module 80. The common control module 80 sends a corresponding signal to its common control output 86, which is connected to the control device input 64. This corresponding signal is used by the controller 62 to determine how many amplifiers should be in the active state and how many should be in the inactive state to provide the required gain. As discussed above, after such evaluation, the controller sends signals to the modules to activate the required modules and to deactivate the unneeded modules.

The common control module 80 shown in Fig. 4 performs the splitter/combiner monitoring and configuration function of the splitter/combiner controller 400 of Fig. 1. The common control module 80 is coupled to the amplifier modules 28, 29, 30, 31 and thus monitors which of the modules 28, 29, 30, 31 are active and which are inactive. Like the functionality 400 of Fig. 1, the common control module 80 configures the combiner 16 and the splitter 54 according to the number of amplifier modules in operation. The configuration is transmitted to the splitter by coupling the module 80 to the splitter 82, 90. Likewise, the configuration is transmitted to the combiner by coupling the module 80 to the combiner 84, 91.

The embodiment shown in Fig. 4 can be used for conventional central operating sites. The embodiment would not require any further programming of the communication system at the central operating site.

Fig. 5 shows another embodiment of the present invention. The system of Fig. 5 operates in substantially the same manner as the system shown in Figs. 1 and 4. However, instead of monitoring the communication bus as in the system of Fig. 4, the system shown in Fig. 5 is in direct communication with the central operating station 210. The central operating station 210 communicates with a receiver 203 at the cell site by means of radio frequency signals 213. The receiver 203 receives these signals and transmits corresponding signals to the common control input 81. The central operating station 210 can thus send information to the common control module 80. This information is used by the common control module and in turn by the control device 62 to determine how many amplifier modules 28, 29, 30, 31 are in the active state and how many should be in the inactive state. The central operating station 210, the common control module 80 and the control device 62 are pre-programmed so that the central operating station 210 can control the operating state of the amplifier modules by communicating via radio frequency signals 213 with the receiver 203 and in turn with the common control module 80 and the control device 62. The common control module 80 shown in Fig. 5 performs the monitoring and configuration function for the divider/combiner in the same way as the common control module 80 shown in Fig. 4 described above.

Use of the embodiment shown in Fig. 5 in conventional cellular systems would require some programming at the central operating site. The central operating site would need to be set up to communicate with the common control module.

Although the present invention is discussed here in the context of cellular telephone cell sites, it may be used in facilities other than cell sites. For example, it may be used in specialty cellular applications. The present invention may be used in any system that uses multiple channels and provides amplification with multiple amplifier modules.

Radio base stations are well known in the art. Such stations and their operation, including the operation of their components, are generally described in George Calhoun, Wireless Access and the Local Telephone Network 126-135, 241-377 (1992), which is hereby incorporated by reference. FIG. 6 is a schematic representation of one embodiment of a subscriber station 500 incorporating a linear amplifier system 10 in accordance with the present invention. The subscriber station 500 illustrated in FIG. 6 includes a user interface 502 with the subscriber station. Such an interface 502 may include a conventional telephone line, a wirelessly connected remote user interface, a subscriber relay station, or a radio-connected telephone or mobile station. The user interface 502 is coupled to a subscriber line interface system, facilitating communication between the user interface 502 and the subscriber station 500. The line interface system 504 is coupled to an analog/digital conversion system 506 pelt that converts the communication from the user interface 502 (analog) to a digital signal. The analog to digital conversion system 506 is coupled to a modulation system 508 that modulates the digital signal output of the conversion system 506 in a preselected manner. The modulation system 508 is coupled to a linear amplifier system 10 embodying the present invention. The amplifier system 10 amplifies the modulated signal in accordance with the present invention. The linear amplifier system is coupled to a radio system/antenna circuit 510. The radio system 510 prepares the amplified signal for transmission via the antenna 512 coupled to the radio system 510.

The general control device 518 monitors and controls all components of the subscriber station 500. The general control device 518 is coupled to the components via a control circuit 516. The subscriber station 500 is coupled to a voltage supply system 520 which provides the power required for the operation of the station 500.

Claims (17)

1. Linear power amplifier system with: an entrance (14); a divider (16) having an input (18) and a plurality of outputs (20, 21, 22, 23); a plurality of linear power amplifier modules (28, 29, 30, 31), each power amplifier module including an input and an output (42, 43, 44 or 45) and each amplifier input being coupled to at least one divider output; a combiner (54) having a plurality of inputs (300, 301, 302, 304) and an output (56), each combiner input being coupled to at least one amplifier output; a controller (62) containing at least one input (64) and at least one output (66); wherein the system input (14) is coupled to the divider input (18), characterized in that each control output (66) is coupled to at least one amplifier module (28, 29, 30, 31); and the controller (62) is constructed such that, upon detection of a predetermined signal at at least one control input (64), it provides a predetermined control signal at at least one control output of at least one amplifier module, the operating state of each amplifier module responding to its predetermined control signal from the controller. 2. System according to claim 1 and further characterized in that a second control device (400) is coupled to the divider (16) and each amplifier module (28, 29, 30, 31) and is arranged such that upon detecting the operating state of each amplifier module, the second control device configures the divider according to the operating state of each amplifier module. 3. System according to claim 2 and further characterized in that the second control device (400) is coupled to the combiner (54) and is configured such that the second control device, upon detecting the operating state of each amplifier module, configures the combiner according to the operating state of each amplifier module. 4. System according to claim 1 and further characterized in that the control device (62) is coupled to the control terminal (68, 69, 70, 71) of each power amplifier module (28, 29, 30, 31) and to the divider (16) and is arranged such that the control device, upon detecting the operating state of each amplifier module, configures the divider according to the operating state of each amplifier module. 5. System according to one of claims 1 to 4 and further characterized in that at least one input (64) of the control device is coupled to at least one node (56) such that signals at this node are transmitted to the input of the control device. 6. System according to claim 5 and further characterized in that the combiner output (56) is coupled to at least one input (64) of the control device. 7. System according to claim 1 or one of claims 2 to 6 as subclaims of claim 1 and further characterized in that the system has a common control module (80) with at least one common control output (82, 84) and at least one common control input (81, 83, 85), wherein at least one common control output is coupled to at least one input (64) of the control device. 8. System according to claim 7 and further characterized in that at least one common control input (81) is coupled to the output of a receiver (202). 9. System according to claim 8 and further characterized in that the common control input (81) is coupled to a communication bus (96). 10. System according to claim 9 and further characterized in that the communication bus (96) is coupled to at least one transmitter (200, 201, 202, 203). 11. System according to one of claims 8 to 10 and further characterized in that the system further comprises a central operating point (210) which communicates with the receiver (202). 12. The system of claim 11 and further characterized in that the location (210) communicates with the receiver (202) using radio frequency signals (212). 13. System according to one of claims 1 to 12 and further characterized in that the control device (62) and/or the second control device (400) is a microprocessor. 14. System according to claim 7 or one of claims 8 to 13 as subclaims of claim 7 and further characterized in that the common control module (80) is coupled to each amplifier module (42, 43, 44, 45) and the divider (16) and is arranged such that the common control module, upon detecting the operating state of each amplifier module, configures the divider according to the operating state of each amplifier module. 15. A system according to claim 7 or any of claims 8 to 14 as dependent claims of claim 7 and further characterized in that the common control module (80) is coupled to each amplifier module (42, 43, 44, 45) and the combiner (54) and is arranged such that the common control module upon detecting the operating state of each amplifier module of the combiner is configured according to the operating state of each amplifier module. 16. Participant station with: an entrance (14); a linear power amplifier system (10) comprising: a divider (16) having an input (18) and a plurality of outputs (20, 21, 22, 23); a plurality of linear power amplifier modules (28, 29, 30, 31), each power amplifier module including an input and an output (42, 43, 44 or 45) and each amplifier input being coupled to at least one divider output; a combiner (54) having a plurality of inputs (300, 301, 302, 304) and an output (56), each combiner input being coupled to at least one amplifier output; a control device (62) containing at least one input (64) and at least one output (66); wherein the station input (14) is coupled to the divider input (18); a modulation system (508); a radio system (510); and an antenna (512); characterized in that the modulation system (508) is coupled to the station input (14); the combiner (54) is coupled to the radio system (510); the radio system is coupled to the antenna (512); the or each output (66) of the control device is coupled to at least one amplifier module (28, 29, 30, 31); and the control device (62) is designed such that, upon detection of a predetermined control signal at at least one input (64) of the control device, it outputs a predetermined control signal at at least one Output of the control device to at least one amplifier module, the operating state of each amplifier module responding to its predetermined control signal from the control device. 17. Control device for a linear power amplifier system comprising: an entrance (14); a divider (16) with an input (18) and a plurality of outputs (20, 21, 22, 23); a plurality of linear power amplifier modules (28, 29, 30, 31), each power amplifier module including an input and an output (42, 43, 44 or 45) and a control terminal (68, 69, 70, 71) and each amplifier input being coupled to at least one divider output; a combiner (54) having a plurality of inputs (300, 301, 302, 304) and an output (56), each combiner input being coupled to at least one amplifier output; wherein the system input (14) is coupled to the divider input (18); the control device (62) contains at least one input (64) and at least one output (66); characterized in that each control output (66) is coupled during operation to the control terminal (68, 69, 70, 71) of at least one amplifier module (28, 29, 30, 31); and the control device (62) is designed such that, during operation, upon detection of a predetermined signal at at least one input (64) of the control device, it provides a predetermined control signal at at least one control output of at least one amplifier module in order to control its operating state.